Electrical control



0dr. 7, 1%52 |$TER 2,613,253

ELECTRICAL CONTROL Filed Dec, 7, 1946 INVENTOR GEORGE H. LISTER w W t[9% ATTORNEYS Patented Oct. 7, 1952 ELECTRICAL CONTROL George H. Lister,Cleveland, Ohio, assignor to The Electronic Research and ManufacturingGorporation, Cleveland, Ohio, a corporation of Ohio Application December7,1946, Serial No. 714,821

This invention relates to means for segregat- I gate a portion of apower cycle as represented by the wave form of alternating current flow'betweentwo predetermined voltages whereby vari-.

ations in the peak voltage have only 'a slight efiect upon the portionof the power cycle segregated.

Another object of the present invention is to accumulate the effect ofsuccessive power cycle portions, as mentioned above, so as toperform "acontrol operation.

A specific object of the present invention to accumulate the efiect ofsuccessive portions of alternating current power cycles, as mentioneding drawings and description and the essential features thereof will besummarized in the. appended claims.

In the drawings,

Fig. 1 is a diagrammatic view of an electrical circuit embodying myinvention; v

Fig. 2is a diagrammatic view of a modified cirsuit for utilizing myinvention;

V Fig. 3 is; an electrical diagram showing another modification of acircuit .for'utilizing my invention; while Y Fig. 4 is a diagram showina waveform of alternating current flow marked to indicate the effect ofmy control apparatus in segregating a portion of the power cycle for acontrol use. .At the outset, I wish it understooclthat my invention maybe applied toalternating electrical current having any Wave form such assquare, triangular, sine or otherwise- I have chosen to describe myinvention by use of a sine wave diagram and have specifically referredto the sine wave throughout the description for simplicityof language.Those skilled in this art, however, will appreciate that the use of theinvention is not confined tothe sine wave form and, intact, has

even greater advantages when appliedtogsome otherwaveforms. 5 A,

I will first explain the theory underlying the use ofmy invention andwill then later describe one use of my invention together with'modifica-5 Claims. (Cl. 175-320) above, in a thermal element which perform acontrol operation when it has been heated to a predetermined point.

Other objects and advantages of the present. invention will be apparentfrom the accompanytions thereof. Referring first to Fig. 4, if analternating current has the sine wave form indicated in full lines at10, it will provide voltage patterns of similar shape alternately onopposite sides of the zero line I I. For the purpose of the presentdescription, it is immaterial which side of the line H is regarded aspositive or negative. My invention contemplates the use of a gas filledelectronic tube having voltage regulator characteristics. I will laterdescribe two types of tube which may be utilized in carrying out myinvention, but without limiting myself to those two types alone.Assuming we have one such type of tube which regulates the voltage at"volts, such a tube will take a voltage as indicated by the full line 12of Fig. 4 up to a peak l3 of perhaps volts at which the .gasfin the tubeionizes after which the voltage will drop steeply to the 75 volt level,as indicated by the portion 12a of the line 12.

Now, if a second electronic tube similar to that described above isproperly connected in an electrical circuit and having slightly highervoltage regulating characteristics, a portion M of the power cycle willbe segregated between the conducting voltages of the two tubes, and thissegregated portion of the power cycle may be utilized in a controloperation. In Fig. 4 I have indicated by the dot-dash line I 5 thecontrol characteristic of such a second tube. The voltage curve of thissecondtube will rise to a peak I6, say at about volts, at which pointthe gas of the tube will be ionized so that the voltage drops steeply tothe portion -l5aof the line and the tube will regulate at say 105 volts.The values of 75 and 105 volts are taken merely for example. and not ina limit- :ing sense.

In a llOvolt circuit the peak [1 of the sine wavewill be approximatelyvolts plus. If. however, the line voltage should vary, as indicated byabout ten percent increase in the dash line I8 of Fig. 4, the peakvoltage at l9 would be of the order of 171 volts. Applying thecharacteristic curves I2 and I5 of the two voltage regulator tubes tothe sine wave l8, as indicated in dotted lines in Fig. 4, it will benoted that the segregated portion of the power cycle has changed veryslightly. The difference between sine waves I0 and I8 issomewhatexaggerated to show the efiect rather than exact values. In other words,the second voltage regulator tube cuts ofi the peak of the power waveabove the 105 volt level so that variations in peak voltage have littleeffect upon the segregated portion of the power, cycle. Thus. thesegregated portion I4 is quite constant under variations of line voltageand may be at 105 volts.

utilized in various ways to perform control functions, one of which willnow be described. The line voltage may vary over quite a wide range aslong as it is within the firing voltage of the control tubes used.

Referring now to Fig. l, I have shown a source of line voltageLI, L2,the power from which is to be utilized upon the closing of switch tocomplete a circuit. Thereafter, upon the termination of a predeterminedtime period it is desired to energize or deenergize a circuit connectedbetween lines 23 and 24. My invention is utilized to determine this timeperiod.

Line 25 is connected through resistance 26 and line 21 with one terminal28a of tube 28, the other terminal of which 28b is connectedthrough'line 29, relay winding 30a and line 29' to line 3| leading backto L2. The relay armature 381) controls normally open contact 32 andnormally closed contact 33. The relay armature 30c controls nor- -mallyopen contact34 and normally closed contact 35., The armature 30b isconnected byline connected by line'43with line 24 and bylines 43 and 44with line 25.

g Tube 28 isa gas filledtube of the FS typecommonly-used as a starter.for fluorescent lights.

Somewhat diagrammatically I have illustrated thevertical rod 45connected with terminal 28a and the. curved. thermal element 46connected with the terminal 2817. In this well known type of tube thethermal effect of the ionized gas on the, end 46a of'the thermal elementcauses this end to movein a clockwise direction as shown in Fig. 1,until the terminal'bar 46b engages the post '45 whereupon the fullcurrent flows from line 21 to line 29. Tube 28 ionizes at 90 volts andregulates at 75 volts.

The tube 38 is a gas filled tube of the VR type which ionizes at 115volts and which regulates The operation of the deviceof Fig. 1 shouldnow be readilyunderstood. When switch 20 is closed, current flowsthrough line 25, resistance '26 "and line 21 through tube 28, insofarasthe ionized gas of tube 28 is conducting. In other words, therflowof'current through tube 28 is represented by that portionof the sine waveI8 in the first half cycle'and above line I2. :This represents the flowof current from rod 45 to the thermal element 46 during ne half cyclebecause it is well known that the flow in the opposite directionduringthe other half cycle has but a small percentage of the total heatingeffect upon the thermal element. The tube 28 should be properlypolarized to provide whatever heating time is required. If the twocontrol tubes are operated in opposite directions, a smaller heatingefiect per cycle will result than if the two tubes are operated in thesame direction.

All of the current flowing through line 25 and resistance 26 does notpass through tube 28,because tube 38 is also ,connected at this timebetween line Z'Iand'line 3I through contact 33. Therefore, tube 38 atthis time is conducting that portion of the wave ID in the first halfcycle and above the line I5. In other words, this portion of the-powerwave above line I5 is shunted off through tube 38' and is not availableto pass through tube 28. Therefore, the actual-flow through tube 28 isrepresented by the portion I4 of the diagram of Fig. 4. The relay 38a isso chosen that the current segregated in the portion I4 (being only afraction ofa half cycle) is not enough to operate the relay. The abovedescribed half cycle is repeated at "every succeeding half cycle abovethe line I I of Fig. 4 so that successive increments as represented bythe portion I4 are utilized to heat the thermal element'46. When asufiicient heating effect has accumulated in the thermal element 46 dueto these repeated half cycles, the tube 28 short-circuits throughcontactof the elements 46b and 45. Thereupon, the line current flowsthrough lines 21 and 29 to the relay coil'30'a so as to operate therelay.

Upon energization of the relay the armature 36b opens contact 33 andcloses contact 32. Opening contact 33 disconnects tube 38. Closing ofcontact 32 connects line 23 with the power line 3|. Energization of therelay causes armature 38c to open contact-35 and to close contact 34.This by-passes tube 28 so that thereafter the line current flows throughlines 25, 44 and 43 through contact. 34, armature 38c and lines 40 and28 to relay 36a to maintain the relay energized. Thereafter, no furthercurrent flows through, tube'23 and the thermal element 46 quickly coolsoff. The tube 28 cools off quickly, partly because it is a gas filledtube and partly because the thermal element 46 quickly conducts heatalong the normally unheated portion thereof. It will be'notell that line24 is always connected by line 44 with the source LI and therefore, uponoperation of the relay to energize line 23, the controlled circuitconnected between lines23 and 24 will be energized. This will" takeplace a predetermined time after the closing of switch'28 becausetheheating of the thermal element 46 depends upon a pluralityof measuredsegreg'ated'power cycle portions as illustrated at I4 in Fig. 4. Uponthe opening of switch 28, the relay winding 30a is deenergized and meansnot shown re-establishes contact at 33and 35,-while breaking contact at32 and 34. The device is then ready for another similar operation.

The purpose of the variable resistor 42'ist0 provide variations in thetime necessary to energizethe relay winding 30a. 3

In Fig. 2, I have shown a modification utilizing tube 28 in the sameposition and performing the same function as formerly and using a secondtube 48 of the FS type'but having very similar conductingcharacteristics as tube 38 previously described. For instance, if tube28 is an FS2 which regulatesat 75 volts, the tube 48 may be an F54 whichregulates at volts. The characteristic conduction and regulation curveof tube 48 is almost exactly like the dotdash line I5 shown in Fig. 4.The device of Fig. 2 operates exactly like the device of Fig. 1 exceptthat tube 48 is connected between-line 25 and line 29 to by-pass some orthe current which otherwise would pass through tube 28 and all currentpassing through tube 48, prior to the operation of relay 30a, will flowthrough the relay winding 30a, whereas in'Fig. 1, the currentby-passedthrough tube 38 flowed directly from LI to L2 without goingthrough the relay winding. However, the relay winding 30:; of Fig.2 isof the order of one thousand to, two thousand ohms resistance and therelay'i's not operated by the current passing through tubes 28 and 48until the element 46 makes "con tact with'the element 45.

It is believed the operation of Fig. 2 will be readily understood afterthe description given 'lexcep'ttostate that when switch [current newsthrough the tubes 28 and 48 ac- Fig. 4).

01 Fig. and "rurt'h'er comment is unnecessary is closed,

cording to their characteristic curves. The upper portion of the powerwave abovethe -line i5 of Fig. 4 is by-passed through lines' lfl" and50, tube 48 and line I lay -winding a without causing operation"thereof. The portion of the the line [2, as shown diagrammatically inFig. 4 and up to the line-i5 is a segregated portion'of 5i, and passesthrough. the repower wave above the power cycle \vliich' flows throughtube 28,

line 29 and relay winding 3511., without causing operation of the sameuntil the thermal element 46 hasbeen heated by 'aplurality of theseaccumulated segregated power portions I4. (see Here, asin the'caseoffFig. 1', when the thermal element 46 causes the rod i 4611' to touchthe rod the'line' current flows through the" relay winding 30: whichcauses operation 'of' the relay. This'closes contact 34 and openscontact 35 so as to connect the relay winding directly between Ll andL2' lay-passing both tubes28 and 48 so that their thermal elements coolquickly ready for another cycle. same time, the relay closes contact 32andopens "contact 33' so as to energize thecontrol circuitwhich'is-connected between lines 23" and '24, or'to deenergize' acircuitconnected between 22 and 24', a predetermined time after-closingswitch 20. v I

The modification of Fig. 3 utilizes two tubes of the VR type operatingon the same principle as previously described, whereby the tube bypassesthe upper portion of the power wave lying above line-I5 of Fig. 4, andthe tube 56 passes that portion of the power :wave lying between linesl2 and I5 of Fig. ,4.,,,L lere, the segregated portions I l of the powercycle are not utilized to heat a thermal element in the" tube itselflike the element 46 of Figs. 1 and 2 ,'but instead, these successivesegregated portions "of power "cycles are passed through aheatfer'llres'istance 51 which heats the bimetallic-thermal element 58so that the efiect of the successive segregated portions is accumulatedin the'thermal element 58 The tube 56 is of the VR typewhich ionrzes atvolts' ahd regulates at =.l'5 "volts and has a characteristic curve likethat shown'i'at'l2 in Fig. 4.The' tube 55 is a VRIOS typewhich ionizesatf1l5 volts and rgulates at voltsv having the characteristic -curveshown at I5 of Fig. 4. Both of these are gas filled tubes. Obviously thevoltages '75 and 105 are illustrative only.

When the switch 20 is closed, current flows through line 59, resistance60, line 6|, tube 55, line 62, normally closed contact 63, relayarmature 64b, line 65 and line 66, back to L2. This circuit conducts theportion of the power wave lying above the line l5 of Fig. 4. At the sametime, part of the power from Ll flows through line 61, tube 56, line 68and resistance 51 to line 62 and then through contact 63 and lines 65and 66 back to L2. The current flowing in this latter circuit isrepresented by the segregated portion [4 of Fig. 4. When sufficient ofthese segregated portionshave flowed through resistance 51 to heat thethermal element 58, the latter closes contact 61' so that power thenflows from line Ll through lines 59 and 18 through the relay winding 64aand through line 69, thermal element 58, contact 61' and lines 65 and66, back to L2. This operates the relay opening contact 63 and closingcontact At: the

10 so that the relay winding 64a' isnow directly connected between'linescontrolled because of the accumulation of. a numberof carefully measuredpower portions M-accumulated on the thermal. element. 58 to'give acumulative timing effect. J

It will thus be seen'that I mayutilize a plurality. oi segregatedpowerportions. out oi'successive. power cycles to provide a control effect.The'power portions. may be segregated by utilizing'any combination oftubes having appropriate control characteristics such as the two FS typetubesi of Fig: 2, the two VR type tubes of Fig. 3 or one of each type,as illustratedin Fig. 1. The cumulative effect of a plurality ofsegregated power portions is made efiective by heating a thermal element45 as in Figs. 1 and 2 which is an element. within a tube, 'or they maybe accumulated on a thermal element 58in Fig. 3 outsideof atubei. YOther ways of accumulating successive segregated power portions.according to my invention for'other control purposes will'readily' occurto *ItJshould be understood that invention is not limited to the.specific tubes shown. for illustration. Many typeset-tubes may beusedregulating at various voltages so as to utilize the principlesdisclosed above. v w

. It should also be understood that the control circuit, to be energizeda predetermined time after I closing switch 26, need not be controlledby ex- 'ternal contacts but it mightbe connected be.- tween lines 69and. 18 (Fig. .3) in parallel with relay coil 64,42, which is onlyenergized a predetermined time after switch 20 closes.

Referring to Fig.3, I'have shown indot-dash lines how a load X-may beconnected. between lines 59 and 66 by lines 2'! and. 22. In this caseload X is energized as soon aszbutton 2ll2is dc.- pressed,jand thecontrolled circuit at Hi, 15,16 will be affected a predetermined timethereafter.

What I claim is:

1. In combination, a source of alternating current, a space dischargedevice and an associated current limiting resistor in circuit therewith,said device and resistor connected with said source, said device beingadapted to pass current only above a predetermined lower voltage level,a second space discharge device connected in circuit with said sourceand in shunt circuit around said first device and saidcurrent limitingresistor, said second device being adapted to pass current only above apredetermined higher voltage level, whereby said first device passescurrent at each alternating current cycle only between said two voltagelevels, means heated by the current passing said first device, a pair ofcontacts, and said last named means positioned to close said contactsupon receiving a predetermined amount of heat.

2. In combination, a source of alternating current, a space chargedevice and an associated current limiting resistor in circuit therewith,said deViceand re'sistorconnected with said source.

said device comprising a tube filled with gas adapted to be ionized byvoltage applied to said 'tubeafter which current fiows in said tube,said 'tube having two' electrodes oneof which is heated :byv ionizingcurrent in: said tuber-to a. predeter- 'mineddegree to cause saidelectrodes to engage and to conduct the line current from said source,said device being'adapted-to regulate the current flowing at apredetermined lower voltage level when said gas is ionized,a secondspace charge devicelconnected in circuit with said source and in shuntcircuit around said first device and said current limiting resistor,said second device being adapted to pass current only above apredetermined higher voltage level, whereby said first device passescurrent only between said two voltage levels, and a controlled deviceconnected in circuit with said first device and energized'by currentflowing through said first device, said controlled device beinginoperative'when :ener- 'gized by said ionizing current flowing betweensaid electrodes disengaged and being actuated 'by said line currentflowing between said electrodes engaged.

3. The combination of claim 2 including an electrical circuit closer,and means for energizing said'first named space charge devicesimultaneously with operation of said circuit closer,

whereby said controlled device is operatively energized a predeterminedtime after said circuit closer is-operated.

4. In combination, a source of alternating current, a space chargedevice and an associated current limiting resistor in circuit therewith,said device and resistor connected with said source,

said device comprising a: tube filled with gas adapted to be ionized byvoltage applied to said tube after which current flows in said tube,said device being adapted to regulate the current flowing at apredetermined lower voltage level 'when said gas is ionized, a secondspace charge device connected in circuit with said source and inshunt-circuit around said first device and said .currentlimitingresistor, said second device being adapted to pass current only above apredetermined higher voltage level, whereby said first devicepasses'current only between said two voltage levels, a bimetallicthermal element connected in circuit with said first" device to beheated by current passing said first device, a contact adapted to beclosed by said bimetallic elementv only'aiter a plurality ofalternationsci said current source has heated said bimetallic element apredetermined amount, and controlled means connected to be energizedthrough said closed contact.

5. In combination, a source of alternating current, a space chargedevice and an associated current limiting resistor in circuit therewith,said device and resistor connected with said: source, said devicecomprising a tube filled with gas adapted to be ionized by voltageapplied to said tube after which current flows in said tube, said devicebeing adapted to regulate the current flowing ,at a predetermined lowervoltage level when said gas is ionized, a second space charge deviceconnected in circuit with said sourceand in shunt circuit around saidfirst device andsaid current limiting resistor, said second device beingadapted to pass current only above a predetermined highervoltage level,whereby said first device passes current only between said two voltagelevels, a' resistor connected in circuit with said first device tobe'heated by current passing said, first device, a bimetallic thermalelement positioned adjacent said resistor, tobe heated thereby, a'contactadapted to be closedby said bimetallic element only after aplurality of alternations of said current source has heated saidbimetallic element a predetermined amount, and controlled meansconnected to be energized through said closed contact. 3 a? GEORGE H.LISTER.

REFERENCES CITED 7 The-following references are of record in the file ofthis patent:

UNITED. STATES PATENTS

